03:00
Spatial Analysis and Statistical Modeling with R and spmodel
2024 Society for Freshwater Science Conference
Michael Dumelle
EPA (USA)
Ryan Hill
EPA (USA)
6/2/24
Welcome!
Please visit https://usepa.github.io/spatial.sfs2024/ to view the workshop’s accompanying workbook
If necessary, install and load R packages by visiting “Setup” in the workbook’s “Welcome” section
(Optional) Download the workshop slides (instructions in the workbook’s “Welcome” section)
Follow along and have fun!
Who Are We?
Michael Dumelle (he/him/his) is a statistician for the United States Environmental Protection Agency (USEPA). He works primarily on facilitating the survey design and analysis of USEPA’s National Aquatic Resource Surveys (NARS), which characterize the condition of waters across the United States. His primary research interests are in spatial statistics, survey design, environmental and ecological applications, and software development.
Who Are We?
Ryan Hill (he/him/his) is an aquatic ecologist with the U.S. EPA Office of Research and Development. He is interested in how watershed conditions drive differences in freshwater diversity and water quality across the United States. He has worked extensively with federal physical, chemical, and biological datasets to gain insights into the factors affecting water quality and biotic condition of freshwaters across the conterminous US. He has also worked to develop and distribute large datasets of geospatial watershed metrics of streams and lakes for the Agency (EPA’s StreamCat and LakeCat datasets).
Who Are We?
Lara Jansen (she/her/hers) is an aquatic community ecologist and an ORISE postdoctoral fellow working on predictive models of benthic macroinvertebrate communities across the conterminous US in relation to watershed factors. Lara completed her PhD in Environmental Science at Portland State University in 2023, studying the drivers and dynamics of harmful algal blooms in mountain lakes with Dr. Angela Strecker.She obtained a MS in Natural Resource Sciences at Cal Poly Humboldt University with a thesis focused on the downstream impacts of dam flow regulation on benthic macroinvertebrate and algal communities.
Who Are We?
Wade Boys (he/him/his) is a graduate student at the University of Arkansas broadly interested in understanding how aquatic ectotherms will respond to climate change, especially the role of phenotypic plasticity in adapting to a warming world. Wade is a firm believer that science is not finished until it is communicated. In addition to research, he finds great purpose in cultivating community and connecting science to our everyday experiences as humans.
Disclaimer
The views expressed in this workshop are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency. Any mention of trade names, products, or services does not imply an endorsement by the U.S. government or the U.S. Environmental Protection Agency. The U.S. Environmental Protection Agency does not endorse any commercial products, services, or enterprises.
What is spmodel?
spmodel is an R package to fit, summarize, and predict for a variety of spatial statistical models. Some of the things that spmodel can do include:
- Fit spatial linear and generalized linear models for point-referenced and areal (lattice) data
- Compare model fits and inspect model diagnostics
- Predict at unobserved spatial locations (i.e., Kriging)
- And much more!
Why use spmodel?
There are many great spatial modeling packages in R. A few reasons to use spmodel for spatial analysis are that:
-
spmodelsyntax is similar to baseRsyntax for functions likelm(),glm(),summary(), andpredict(), making the transition from fitting non-spatial models to spatial models relatively seamless. - There are a wide variety of
spmodelcapabilities that give the user significant control over the specific spatial model being fit. -
spmodelis compatible with other modernRpackages likebroomandsf.
Spatial Linear Models in spmodel
Goals
- Construct and describe the spatial linear model
- Fit a spatial linear model using
spmodel - Make spatial predictions at unobserved locations (i.e., Kriging).
Construct and Describe the Spatial Linear Model
- Review the nonspatial linear model with independent random errors.
- Explain how the spatial linear model differs from the linear model with independent random errors.
- Explain how modeling for point-referenced data with distance-based model covariances differs from modeling for areal data with neighborhood-based model covariances.
Nonspatial Linear Models
Nonspatial linear models are incredibly flexible tools that quantify the relationship between a response variable and a set of explanatory variables
Examples of nonspatial linear models: multiple linear regression, analysis of variance (ANOVA), splines, polynomial regression, additive models, and mixed effect models
\[ \begin{split} \text{y} & = \beta_0 + \beta_1 x_1 + \beta_2 x_2 + \dots + \beta_k + \epsilon \\ i & = 1, 2, \dots, k \end{split} \]
Nonspatial Linear Models
Generalizing becomes
\[ \begin{split} \text{y}_j & = \beta_0 + \beta_1 x_{1, j} + \beta_2 x_{2, j} + \dots + \beta_k x_{k, j} + \epsilon_j \\ i & = 1, 2, \dots, k \\ j & = 1, 2, \dots, n \end{split} \]
Nonspatial Linear Models
Matrix notation:
\[ \mathbf{y} = \begin{bmatrix} \text{y}_1 \\ \text{y}_2 \\ \vdots \\ \text{y}_j \\ \end{bmatrix}, \mathbf{X} = \begin{bmatrix} 1 & x_{1, 1} & x_{1, 2} & \dots & x_{1, k} \\ 1 & x_{2, 1} & x_{2, 2} & \dots & x_{2, k} \\ \vdots & \vdots & \vdots & \vdots & \vdots \\ 1 & x_{n, 1} & x_{n, 2} & \dots & x_{n, k} \\ \end{bmatrix}, \]
Nonspatial Linear Models
Matrix notation:
\[ \boldsymbol{\beta} = \begin{bmatrix} \beta_0 \\ \beta_1 \\ \vdots \\ \beta_k \end{bmatrix}, \text{ and } \boldsymbol{\epsilon} = \begin{bmatrix} \epsilon_0 \\ \epsilon_1 \\ \vdots \\ \epsilon_j \end{bmatrix}, \] The nonspatial linear model is written as \[ \mathbf{y} = \mathbf{X} \boldsymbol{\beta} + \boldsymbol{\epsilon} \]
Your Turn
Introduce yourself to one (or more) neighbor(s)! What kinds of data have you used statistical modeling for? Have you ever used linear models via lm() in R?
Spatial Linear Models
- Ignoring this spatial dependence and fitting nonspatial linear models (for spatially dependent data) generally leads to invalid fixed effect inference and poor predictions
- Spatial linear models leverage spatial dependence to improve model fit.
- Models historically challenging, theoretically and computationally
- Fortunately,
spmodelmakes it straightforward to implement these models.
Spatial Linear Models
- Add a spatially dependent random error (\(\boldsymbol{\tau}\)) that accounts for dependence (i.e., covariance, correlation) in space
\[ \mathbf{y} = \mathbf{X} \boldsymbol{\beta} + \boldsymbol{\tau} + \boldsymbol{\epsilon}, \]
- Can choose various ways to describe the covariance in \(\boldsymbol{\tau}\) (exponential, Gaussian, autoregressive, etc.)
- Applies to point-referenced (e.g., locations in a field) and areal data (e.g., counties in a state)
-
splm()andspautor()
Fit a Spatial Linear Model Using spmodel
- Explore the
splm()function using themossdata. - Connect parameter estimates in the summary output of
splm()to the spatial linear model.
The moss Data
The moss data contains a variable for log Zinc concentration for moss samples collected near a mining road in Alaska.
The moss Data
The moss Data
| sideroad | log_dist2road | log_Zn | geometry |
|---|---|---|---|
| N | 2.68 | 7.33 | POINT (-413585.3 1997623) |
| N | 2.68 | 7.38 | POINT (-413585.3 1997623) |
| N | 2.54 | 7.58 | POINT (-415367.2 1996769) |
The splm() function
The splm() function shares syntactic structure with the lm() function and generally requires at least three arguments
-
formula: a formula that describes the relationship between the response variable (\(\mathbf{y}\)) and explanatory variables (\(\mathbf{X}\)) -
data: adata.frameorsfobject that contains the response variable, explanatory variables, and spatial information. -
spcov_type: the spatial covariance type ("exponential","Gaussian","spherical", etc; 17 total types)
The splm() function
spmod <- splm(formula = log_Zn ~ log_dist2road, data = moss,
spcov_type = "exponential")
summary(spmod)
Call:
splm(formula = log_Zn ~ log_dist2road, data = moss, spcov_type = "exponential")
Residuals:
Min 1Q Median 3Q Max
-2.6801 -1.3606 -0.8103 -0.2485 1.1298
Coefficients (fixed):
Estimate Std. Error z value Pr(>|z|)
(Intercept) 9.76825 0.25216 38.74 <2e-16 ***
log_dist2road -0.56287 0.02013 -27.96 <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Pseudo R-squared: 0.683
Coefficients (exponential spatial covariance):
de ie range
3.595e-01 7.897e-02 8.237e+03 Separating Sources of Variation
- Pseudo R-squared: The proportion of variability explained by the fixed effects
- de: The proportion of variability attributable to spatial random error
- ie: The proportion of variability attributable to independent random error
Tidying Output
The tidy() function tidies fixed effect model output into a convenient tibble (a special data.frame)
# A tibble: 2 × 5
term estimate std.error statistic p.value
<chr> <dbl> <dbl> <dbl> <dbl>
1 (Intercept) 9.77 0.252 38.7 0
2 log_dist2road -0.563 0.0201 -28.0 0- When
log_dist2roadis zero, the averagelog_Znvalue is 9.768 - A one unit increase in
log_dist2roadis associated with an average decrease of 0.563 inlog_Zn
Tidying Output
It can also be used to tidy spatial covariance parameters
# A tibble: 3 × 3
term estimate is_known
<chr> <dbl> <lgl>
1 de 0.360 FALSE
2 ie 0.0790 FALSE
3 range 8237. FALSE -
range: A parameter that controls the distance-decay rate of the spatial covariance
Model Fit
The glance() function returns columns with the sample size (n), number of fixed effects (p), number of estimated covariance parameters (npar), optimization criteria minimum (value), AIC (AIC), AICc (AICc), log-likelihood (loglik), deviance (deviance), and pseudo R-squared (pseudo.r.squared)
Model Diagnostics
The augment() function returns columns with
-
.fitted, the fitted value, calculated from the estimated fixed effects in the model -
.resid, the raw residual (observed minus fitted) -
.hat, the Mahalanobis distance, a metric of leverage -
.cooksd, the Cook’s distance, a metric of influence -
.std.resid, the standardized residual
Model Diagnostics
Simple feature collection with 365 features and 7 fields
Geometry type: POINT
Dimension: XY
Bounding box: xmin: -445884.1 ymin: 1929616 xmax: -383656.8 ymax: 2061414
Projected CRS: NAD83 / Alaska Albers
# A tibble: 365 × 8
log_Zn log_dist2road .fitted .resid .hat .cooksd .std.resid
* <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 7.33 2.68 8.26 -0.928 0.0200 0.0142 1.18
2 7.38 2.68 8.26 -0.880 0.0200 0.0186 1.35
3 7.58 2.54 8.34 -0.755 0.0225 0.00482 0.647
4 7.63 2.97 8.09 -0.464 0.0197 0.0305 1.74
5 7.26 2.72 8.24 -0.977 0.0215 0.131 3.45
6 7.65 2.76 8.21 -0.568 0.0284 0.0521 1.89
7 7.59 2.30 8.47 -0.886 0.0300 0.0591 1.96
8 7.16 2.78 8.20 -1.05 0.0335 0.00334 0.439
9 7.19 2.93 8.12 -0.926 0.0378 0.0309 1.26
10 8.07 2.79 8.20 -0.123 0.0314 0.00847 0.723
# ℹ 355 more rows
# ℹ 1 more variable: geometry <POINT [m]>Your Turn
Run the fitted(), residuals(), hatvalues(), cooks.distance(), and rstandard() functions and verify they return the same values as augment().
05:00
Plotting Model Objects
The plot() function can be used on a fitted model object to construct a few pre-specified plots of these model diagnostics. For example, the following code plots the Cook’s distance, a measure of influence, which quantifies each observation’s impact on model fit:
Powerful to combine diagnostics with spatial visualizations via augment()
Plotting Model Objects
Your Turn
Use spmodel’s plot function on the spmod object to construct a plot of the fitted spatial covariance vs spatial distance. To learn more about the options for spmodel’s plot function, run ?plot.spmodel.
03:00
Model Comparison
- Fit a nonspatial linear model using
splm()andspcov_type = "none"
Your Turn
Using sumamry(), compare the output of the none model fit via splm() to a model fit via lm(). Do you get the same estimates and standard errors?
03:00
AIC and AICc
-
glances()lets us compare the fit of several models simultaneously - The lower the AIC/AICc, the better the fit
# A tibble: 2 × 10
model n p npar value AIC AICc logLik deviance pseudo.r.squared
<chr> <int> <dbl> <int> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 spmod 365 2 3 367. 373. 373. -184. 363. 0.683
2 none 365 2 1 634. 636. 636. -317. 363. 0.671- The spatial model has a much lower AIC/AICc
- We do not recommend comparing pseudo R-squared across models
REML vs ML
- The default estimation method is restricted maximum likelihood (REML,
estmethod = "reml") - To compare models having different fixed effect structures with AIC/AICc, the models must be fit using maximum likelihood (ML,
estmethod = "ml") - Generally few differences between REML and ML unless sample sizes are small
- When sample sizes are small, REML can notably outperform ML
- Refit a “final” model using REML (more on this)
Leave-One-Out Cross Validation
Leave-one-out cross validation (loocv):
- Hold-out observation one, fit model to rest of data and predict observation one
- Hold-out observation two, fit model to rest of data and predict observation two
- …
- Hold-out observation \(n\), fit model to rest of data and predict observation \(n\)
- Compare observed data to loocv predictions
Leave-One-Out Cross Validation
loocv() returns several useful fit statistics:
-
bias: The average difference between the observed value and its leave-one-out prediction. This should be close to zero for well-fitting models. -
MSPE: The mean squared prediction error between the observed value and its leave-one-out prediction. -
RMSPE: The square root ofMSPE. -
cor2: The squared correlation between the observed value and its leave-one-out prediction. Can be viewed as a “predictive” R-squared (can be compared across models).
Leave-One-Out Cross Validation
# A tibble: 1 × 4
bias MSPE RMSPE cor2
<dbl> <dbl> <dbl> <dbl>
1 0.00655 0.111 0.333 0.886# A tibble: 1 × 4
bias MSPE RMSPE cor2
<dbl> <dbl> <dbl> <dbl>
1 0.000644 0.324 0.569 0.667- The spatial model has a much lower (better)
MSPE/RMSPEand higher (better)cor2. - Unlike AIC/AICc,
loocv()can be used to compare two models fit using REML that have different fixed effect structures
Model Comparison Strategies
- All models are wrong, but some are useful
- Model selection is quite a challenging problem
- Fit a single hypothesized model? Use an algorithm to find a model? Somewhere in between?
- Combine expert knowledge of the system with empirical tools to aid decision making
- Generally, fit the “final” model using REML
Spatial Prediction (i.e., Kriging)
- Predict the response value at an unobserved location for point-referenced data using the
moosedata. - Quantify prediction uncertainty.
- Perform leave-one-out cross-validation
The moose Data
- We will practice with some new data in
spmodelcalledmoose(andmoose_preds) - The
moosedata contains moose counts and moose presence for 218 spatial locations in Alaska.
The moose Data
The moose Data
| elev | strat | count | presence | geometry |
|---|---|---|---|---|
| 469 | L | 0 | 0 | POINT (293542.6 1541016) |
| 362 | L | 0 | 0 | POINT (298313.1 1533972) |
| 173 | M | 0 | 0 | POINT (281896.4 1532516) |
The moose_preds Data
- The
moose_predsdata contains spatial locations that were not surveyed for which predictions are desired
The moose_preds Data
The moose_preds Data
| elev | strat | geometry |
|---|---|---|
| 143.4000 | L | POINT (401239.6 1436192) |
| 324.4375 | L | POINT (352640.6 1490695) |
| 158.2632 | L | POINT (360954.9 1491590) |
Fit a Spatial Linear Model
-
elev * stratis shorthand forelev + strat + elev:strat
# A tibble: 4 × 5
term estimate std.error statistic p.value
<chr> <dbl> <dbl> <dbl> <dbl>
1 (Intercept) 0.310 9.02 0.0344 0.973
2 elev 0.0141 0.00806 1.76 0.0792
3 stratM 6.93 2.26 3.07 0.00217
4 elev:stratM -0.0273 0.0130 -2.10 0.0357 - A linear model for count data? (more on this later)
Spatial Predictions For moose_preds
Using predict()
Using augment()
Spatial Predictions For moose_preds
Simple feature collection with 100 features and 3 fields
Geometry type: POINT
Dimension: XY
Bounding box: xmin: 269386.2 ymin: 1418453 xmax: 419976.2 ymax: 1541763
Projected CRS: NAD83 / Alaska Albers
# A tibble: 100 × 4
elev strat .fitted geometry
* <dbl> <chr> <dbl> <POINT [m]>
1 143. L 3.45 (401239.6 1436192)
2 324. L 1.59 (352640.6 1490695)
3 158. L -0.267 (360954.9 1491590)
4 221. M 2.39 (291839.8 1466091)
5 209. M 7.62 (310991.9 1441630)
6 218. L -1.02 (304473.8 1512103)
7 127. L -1.23 (339011.1 1459318)
8 122. L -1.43 (342827.3 1463452)
9 191 L -0.239 (284453.8 1502837)
10 105. L 0.657 (391343.9 1483791)
# ℹ 90 more rowsSpatial Predictions For moose_preds
We can construct a plot of the predictions with
Spatial Predictions For moose_preds
Your Turn
Examine the help file ?augment.spmodel or by visiting this link and create site-wise 99% prediction intervals for the unsampled locations found in moose_preds.
05:00
Additional Features
Applications to:
- Big spatial data
- Nonspatial random effects
- Simulating spatial data
- And much more!
- See Chapter 2 of the workbook
Spatial Generalized Linear Models in spmodel
Goals
- Explain how modeling spatial covariance fits within the structure of a generalized linear model.
- Use the
spglm()function inspmodelto fit generalized linear models for various model families (i.e., response distributions).
The Spatial Generalized Linear Model
The spatial generalized linear model can be written as
\[ g(\boldsymbol{\mu}) = \mathbf{X} \boldsymbol{\beta} + \boldsymbol{\tau} + \boldsymbol{\epsilon}, \]
- \(g(\boldsymbol{\mu})\) is the link function that “links” a function of the mean of \(\mathbf{y}\) to \(\mathbf{X} \boldsymbol{\beta}\), \(\boldsymbol{\tau}\), and \(\boldsymbol{\epsilon}\)
Response Distributions
| Distribution | Data Type | Link Function |
|---|---|---|
| Poisson | Count | Log |
| Negative Binomial | Count | Log |
| Binomial | Binary | Logit |
| Beta | Proportion | Logit |
| Gamma | Skewed | Log |
| Inverse Gaussian | Skewed | Log |
The moose Data
| elev | strat | count | presence | geometry |
|---|---|---|---|---|
| 468.9 | L | 0 | 0 | POINT (293542.6 1541016) |
| 362.3 | L | 0 | 0 | POINT (298313.1 1533972) |
| 172.8 | M | 0 | 0 | POINT (281896.4 1532516) |
Fit a Spatial Generalized Model
- What about a count model for moose?
- The
familyargument can bebinomial,beta,poisson,nbinomial,Gamma, orinverse.gaussian - Similarities between
spglm()andglm()
Fit a Spatial Generalized Model
Call:
spglm(formula = count ~ elev * strat, family = poisson, data = moose,
spcov_type = "spherical")
Deviance Residuals:
Min 1Q Median 3Q Max
-1.4245 -0.7783 -0.3653 0.1531 0.5900
Coefficients (fixed):
Estimate Std. Error z value Pr(>|z|)
(Intercept) -2.230575 0.958201 -2.328 0.019919 *
elev 0.007623 0.003129 2.437 0.014820 *
stratM 2.752234 0.782853 3.516 0.000439 ***
elev:stratM -0.010248 0.004472 -2.292 0.021928 *
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Pseudo R-squared: 0.09573
Coefficients (spherical spatial covariance):
de ie range
3.892 1.163 51204.657
Coefficients (Dispersion for poisson family):
dispersion
1 Your Turn
Fit a spatial negative binomial model to the moose data with count as the response, elev, strat, and their interaction as predictors, and the "gaussian" spatial covariance function. Compare their fits using glances() and loocv(). Which model is preferable based on AIC/AICc? What about leave-one-out MSPE?
05:00
Spatial Predictions for moose_preds
Using predict()
Using augment()
Spatial Predictions for moose_preds
Simple feature collection with 100 features and 3 fields
Geometry type: POINT
Dimension: XY
Bounding box: xmin: 269386.2 ymin: 1418453 xmax: 419976.2 ymax: 1541763
Projected CRS: NAD83 / Alaska Albers
# A tibble: 100 × 4
elev strat .fitted geometry
* <dbl> <chr> <dbl> <POINT [m]>
1 143. L 0.207 (401239.6 1436192)
2 324. L -0.0563 (352640.6 1490695)
3 158. L -1.24 (360954.9 1491590)
4 221. M -1.16 (291839.8 1466091)
5 209. M 1.78 (310991.9 1441630)
6 218. L -1.84 (304473.8 1512103)
7 127. L -2.80 (339011.1 1459318)
8 122. L -2.45 (342827.3 1463452)
9 191 L -0.409 (284453.8 1502837)
10 105. L -1.10 (391343.9 1483791)
# ℹ 90 more rowsYour Turn
Use spglm() to fit a spatial logistic regression model to the moose data using presence as the response variable and a Cauchy covariance function. Then, find the predicted probabilities that moose are present at the spatial locations in moose_preds (Hint: Use the type argument in predict() or augment()).
05:00
GIS in R
Maintaining all analyses within a single software (R) can greatly simplify your research workflow. In this section, we’ll cover the basics of doing GIS in R.
Goals and Motivation
- Understand the main features and types of vector data.
- Generate point data from a set of latitudes and longitudes, such as from fields sites.
- Read, write, query, and manipulate vector data using the
sfpackage.
Points, lines, and polygons
Points, lines, and polygons
We can represent these features in R without actually using GIS packages.
library(tidyverse)
library(ggplot2)
id <- c(1:5)
cities <- c('Ashland','Corvallis','Bend','Portland','Newport')
longitude <- c(-122.699, -123.275, -121.313, -122.670, -124.054)
latitude <- c(42.189, 44.57, 44.061, 45.523, 44.652)
population <- c(20062, 50297, 61362, 537557, 9603)
oregon_cities <- data.frame(id, cities, longitude, latitude, population)Points, lines, and polygons
Points, lines, and polygons
Points, lines, and polygons
So, is this sufficient for working with spatial data in R and doing spatial analysis? What are we missing?
If you have worked with vector data before, you may know that these data also usually have:
- A coordinate reference system
- A bounding box or extent
- Plot order
- Additional data
Exploring the Simple Features (sf) package
- The
sfpackage provides simple features access forR -
sffits in within the “tidy” approach to data of Hadley Wickham’stidyverse - In short, much of what used to require ArcGIS license can now be done in
Rwithsf
Exploring the Simple Features (sf) package
[1] "%>%" "as_Spatial"
[3] "dbDataType" "dbWriteTable"
[5] "gdal_addo" "gdal_create"
[7] "gdal_crs" "gdal_extract"
[9] "gdal_inv_geotransform" "gdal_metadata"
[11] "gdal_polygonize" "gdal_rasterize"
[13] "gdal_read" "gdal_read_mdim"
[15] "gdal_subdatasets" "gdal_utils"
[17] "gdal_write" "gdal_write_mdim"
[19] "get_key_pos" "NA_agr_"
[21] "NA_bbox_" "NA_crs_"
[23] "NA_m_range_" "NA_z_range_"
[25] "plot_sf" "rawToHex"
[27] "read_sf" "sf.colors"
[29] "sf_add_proj_units" "sf_extSoftVersion"
[31] "sf_proj_info" "sf_proj_network"
[33] "sf_proj_pipelines" "sf_proj_search_paths"
[35] "sf_project" "sf_use_s2"
[37] "st_agr" "st_agr<-"
[39] "st_area" "st_as_binary"
[41] "st_as_grob" "st_as_s2"
[43] "st_as_sf" "st_as_sfc"
[45] "st_as_text" "st_axis_order"
[47] "st_bbox" "st_bind_cols"
[49] "st_boundary" "st_break_antimeridian"
[51] "st_buffer" "st_can_transform"
[53] "st_cast" "st_centroid"
[55] "st_collection_extract" "st_combine"
[57] "st_concave_hull" "st_contains"
[59] "st_contains_properly" "st_convex_hull"
[61] "st_coordinates" "st_covered_by"
[63] "st_covers" "st_crop"
[65] "st_crosses" "st_crs"
[67] "st_crs<-" "st_delete"
[69] "st_difference" "st_dimension"
[71] "st_disjoint" "st_distance"
[73] "st_drivers" "st_drop_geometry"
[75] "st_equals" "st_equals_exact"
[77] "st_filter" "st_geometry"
[79] "st_geometry_type" "st_geometry<-"
[81] "st_geometrycollection" "st_graticule"
[83] "st_inscribed_circle" "st_interpolate_aw"
[85] "st_intersection" "st_intersects"
[87] "st_is" "st_is_empty"
[89] "st_is_longlat" "st_is_simple"
[91] "st_is_valid" "st_is_within_distance"
[93] "st_jitter" "st_join"
[95] "st_layers" "st_length"
[97] "st_line_interpolate" "st_line_merge"
[99] "st_line_project" "st_line_sample"
[101] "st_linestring" "st_m_range"
[103] "st_make_grid" "st_make_valid"
[105] "st_minimum_rotated_rectangle" "st_multilinestring"
[107] "st_multipoint" "st_multipolygon"
[109] "st_nearest_feature" "st_nearest_points"
[111] "st_node" "st_normalize"
[113] "st_overlaps" "st_perimeter"
[115] "st_point" "st_point_on_surface"
[117] "st_polygon" "st_polygonize"
[119] "st_precision" "st_precision<-"
[121] "st_read" "st_read_db"
[123] "st_relate" "st_reverse"
[125] "st_sample" "st_segmentize"
[127] "st_set_agr" "st_set_crs"
[129] "st_set_geometry" "st_set_precision"
[131] "st_sf" "st_sfc"
[133] "st_shift_longitude" "st_simplify"
[135] "st_snap" "st_sym_difference"
[137] "st_touches" "st_transform"
[139] "st_triangulate" "st_triangulate_constrained"
[141] "st_union" "st_viewport"
[143] "st_voronoi" "st_within"
[145] "st_wrap_dateline" "st_write"
[147] "st_write_db" "st_z_range"
[149] "st_zm" "vec_cast.sfc"
[151] "vec_ptype2.sfc" "write_sf" Exploring the Simple Features (sf) package
- Convert the existing oregon cities data frame to a simple feature by:
- Supplying the longitude and latitude (x and y).
- Defining the (geographic) coordinate reference system (
crs).
Exploring the Simple Features (sf) package
oregon_cities <- oregon_cities %>%
st_as_sf(coords = c('longitude', 'latitude'), crs = 4269)
print(oregon_cities)Simple feature collection with 5 features and 3 fields
Geometry type: POINT
Dimension: XY
Bounding box: xmin: -124.054 ymin: 42.189 xmax: -121.313 ymax: 45.523
Geodetic CRS: NAD83
id cities population geometry
1 1 Ashland 20062 POINT (-122.699 42.189)
2 2 Corvallis 50297 POINT (-123.275 44.57)
3 3 Bend 61362 POINT (-121.313 44.061)
4 4 Portland 537557 POINT (-122.67 45.523)
5 5 Newport 9603 POINT (-124.054 44.652)Exploring the Simple Features (sf) package
The oregon_cities object has now changed from being a standard data frame and includes features that are required for a true spatial object.
- Geometry type
- Bounding box
- Coordinate reference system
Latitude and longitude columns have been moved to a new column called "geometry" (sticky).
Coordinate Reference Systems
sf also has functionality to re-project and manipulate spatial objects.
Coordinate Reference Systems
oregon_cities is currently in degrees, but certain applications may require an equal area projection and length units, such as meters. See: epsg.org
With sf we can:
- Check to see if the current CRS is equal to the Albers Equal-Area Conic Projection
- Transform
oregon_citiesto CRS 5070
Coordinate Reference Systems
Coordinate Reference Systems
Now let’s plot the the transformed data…
Coordinate Reference Systems
It all feels like R
- There can be huge advantages to doing GIS tasks in
Rwithout going back and forth to other GIS software - If you are familiar with
R, the leap to doing GIS here can be small -
sfprovides a large number of GIS functions, such as buffers, intersection, centroids, etc.
It all feels like R
Example 1: Add 100 Km buffer to cities
Plot map of buffered cities…
It all feels like R
It all feels like R
Example 2: Split buffers into sub-units and calculate areas
Plot results:
It all feels like R
Raster data
- Another fundamental data type in GIS is the raster
- Rasters are a way of displaying gridded data, where each member of the grid represents a landscape feature (e.g., elevation)
- The
terrapackage is now the best package for working with rasters
Raster data
Much like sf, terra has a large number of functions for working with raster data.
[1] "%in%" "activeCat" "activeCat<-"
[4] "add_box" "add_legend" "add<-"
[7] "addCats" "adjacent" "aggregate"
[10] "align" "all.equal" "allNA"
[13] "animate" "app" "approximate"
[16] "area" "Arith" "as.array"
[19] "as.bool" "as.contour" "as.data.frame"
[22] "as.factor" "as.int" "as.lines"
[25] "as.list" "as.matrix" "as.points"
[28] "as.polygons" "as.raster" "atan_2"
[31] "atan2" "autocor" "barplot"
[34] "blocks" "boundaries" "boxplot"
[37] "buffer" "cartogram" "catalyze"
[40] "categories" "cats" "cbind2"
[43] "cellFromRowCol" "cellFromRowColCombine" "cellFromXY"
[46] "cells" "cellSize" "centroids"
[49] "clamp" "clamp_ts" "classify"
[52] "clearance" "click" "colFromCell"
[55] "colFromX" "colorize" "coltab"
[58] "coltab<-" "combineGeoms" "compare"
[61] "Compare" "compareGeom" "concats"
[64] "contour" "convHull" "costDist"
[67] "countNA" "cover" "crds"
[70] "crop" "crosstab" "crs"
[73] "crs<-" "datatype" "deepcopy"
[76] "delaunay" "densify" "density"
[79] "depth" "depth<-" "describe"
[82] "diff" "direction" "disagg"
[85] "distance" "dots" "draw"
[88] "droplevels" "elongate" "emptyGeoms"
[91] "erase" "expanse" "ext"
[94] "ext<-" "extend" "extract"
[97] "extractAlong" "extractRange" "fileBlocksize"
[100] "fillHoles" "fillTime" "flip"
[103] "focal" "focal3D" "focalCor"
[106] "focalCpp" "focalMat" "focalPairs"
[109] "focalReg" "focalValues" "forceCCW"
[112] "free_RAM" "freq" "gaps"
[115] "gdal" "gdalCache" "geom"
[118] "geomtype" "getGDALconfig" "getTileExtents"
[121] "global" "graticule" "gridDist"
[124] "gridDistance" "halo" "has.colors"
[127] "has.RGB" "has.time" "hasMinMax"
[130] "hasValues" "head" "hist"
[133] "identical" "ifel" "image"
[136] "impose" "inext" "init"
[139] "inMemory" "inset" "interpIDW"
[142] "interpNear" "interpolate" "intersect"
[145] "is.bool" "is.empty" "is.factor"
[148] "is.int" "is.lines" "is.lonlat"
[151] "is.points" "is.polygons" "is.related"
[154] "is.rotated" "is.valid" "isFALSE"
[157] "isTRUE" "k_means" "lapp"
[160] "layerCor" "levels" "linearUnits"
[163] "lines" "logic" "Logic"
[166] "longnames" "longnames<-" "makeNodes"
[169] "makeTiles" "makeValid" "makeVRT"
[172] "map.pal" "mask" "match"
[175] "math" "Math" "Math2"
[178] "mean" "median" "mem_info"
[181] "merge" "mergeLines" "mergeTime"
[184] "meta" "metags" "metags<-"
[187] "minCircle" "minmax" "minRect"
[190] "modal" "mosaic" "na.omit"
[193] "NAflag" "NAflag<-" "names"
[196] "ncell" "ncol" "ncol<-"
[199] "nearby" "nearest" "nlyr"
[202] "nlyr<-" "noNA" "normalize.longitude"
[205] "north" "not.na" "nrow"
[208] "nrow<-" "nsrc" "origin"
[211] "origin<-" "pairs" "panel"
[214] "patches" "perim" "persp"
[217] "plet" "plot" "plotRGB"
[220] "points" "polys" "prcomp"
[223] "predict" "princomp" "project"
[226] "quantile" "query" "rangeFill"
[229] "rapp" "rast" "rasterize"
[232] "rasterizeGeom" "rasterizeWin" "rcl"
[235] "readRDS" "readStart" "readStop"
[238] "readValues" "rectify" "regress"
[241] "relate" "removeDupNodes" "res"
[244] "res<-" "resample" "rescale"
[247] "rev" "RGB" "RGB<-"
[250] "roll" "rotate" "round"
[253] "rowColCombine" "rowColFromCell" "rowFromCell"
[256] "rowFromY" "same.crs" "sapp"
[259] "saveRDS" "sbar" "scale"
[262] "scoff" "scoff<-" "sds"
[265] "segregate" "sel" "selectHighest"
[268] "selectRange" "serialize" "set.cats"
[271] "set.crs" "set.ext" "set.names"
[274] "set.RGB" "set.values" "setGDALconfig"
[277] "setMinMax" "setValues" "shade"
[280] "sharedPaths" "shift" "sieve"
[283] "simplifyGeom" "size" "snap"
[286] "sort" "sources" "spatSample"
[289] "spin" "split" "sprc"
[292] "stdev" "stretch" "subset"
[295] "subst" "summary" "Summary"
[298] "svc" "symdif" "t"
[301] "tail" "tapp" "terrain"
[304] "terraOptions" "text" "tighten"
[307] "time" "time<-" "timeInfo"
[310] "tmpFiles" "trans" "trim"
[313] "union" "unique" "units"
[316] "units<-" "unserialize" "unwrap"
[319] "update" "values" "values<-"
[322] "varnames" "varnames<-" "vect"
[325] "vector_layers" "viewshed" "voronoi"
[328] "vrt" "vrt_tiles" "weighted.mean"
[331] "where.max" "where.min" "which.lyr"
[334] "which.max" "which.min" "width"
[337] "window" "window<-" "wrap"
[340] "wrapCache" "writeCDF" "writeRaster"
[343] "writeStart" "writeStop" "writeValues"
[346] "writeVector" "xapp" "xFromCell"
[349] "xFromCol" "xmax" "xmax<-"
[352] "xmin" "xmin<-" "xres"
[355] "xyFromCell" "yFromCell" "yFromRow"
[358] "ymax" "ymax<-" "ymin"
[361] "ymin<-" "yres" "zonal"
[364] "zoom" Raster data
Create and define raster
class : SpatRaster
dimensions : 10, 10, 1 (nrow, ncol, nlyr)
resolution : 36, 18 (x, y)
extent : -180, 180, -90, 90 (xmin, xmax, ymin, ymax)
coord. ref. : lon/lat WGS 84
source(s) : memory
name : lyr.1
min value : 0.01871994
max value : 0.99392609 Raster data
Basic raster in R.
Raster data
We can access data from specific locations within a raster
Raster data
Rasters can be stacked which can make them very efficient to work with
Raster data
Working with real data
- There are several packages for accessing geospatial data from the web
- We will use the
FedDatapackage, but numerous other packages exist to access data within and without the U.S. - One useful example is the
elevatrpackage for accessing elevation data around the world
Working with real data
We will walk through an example of extracting information from a raster using a polygon layer. To do this we will:
- Select just Corvallis among
oregon_cities - Add a 10,000m buffer
- Download National Elevation Data
- Transform the projection system of the elevation data to match Corvallis
- Calculate the average elevation within 10km of Corvallis
Working with real data
- Buffer Corvallis
Working with real data
- Download NED based on Corvallis buffer
- Transform the CRS
Working with real data
- Mean elevation within polygon
Your Turn
- Read in U.S. cities with
data('us.cities')from themapslibrary - Select the city of your choice and buffer it by 10Km. (We suggest converting to an equal area projection first)
- Read in National Elevation Data for your city with the
FedDatapackage - Transform CRS of elevation data to match city
- Calculate the mean elevation within 10km of your city
08:00
Solution
1-2. Buffer city of your choice
Solution
- Read in elevation data
Solution
- Transform CRS
Solution
- Calculate mean elevation within buffer
Watershed Delineation
- Characterizing watersheds is fundamental to much of our work in freshwater science
- Although it is more than we can cover in today’s workshop, we want you to be aware that there are several options for delineating watersheds in
R - We’ll provide two examples of how to delineate watersheds within the conterminous U.S. using two online services
USGS StreamStats
The USGS’s StreamStats is an online service and map interface that allows users to navigate to a desired location and delineate a watershed boundary with the click of a mouse:
https://streamstats.usgs.gov/ss/
In addition to the map interface, the data are also accessible via an API:
USGS StreamStats
It is also possible to replicate this functionality in R:
streamstats_ws = function(state, longitude, latitude){
p1 = 'https://streamstats.usgs.gov/streamstatsservices/watershed.geojson?rcode='
p2 = '&xlocation='
p3 = '&ylocation='
p4 = '&crs=4269&includeparameters=false&includeflowtypes=false&includefeatures=true&simplify=true'
query <- paste0(p1, state, p2, toString(longitude), p3, toString(latitude), p4)
mydata <- jsonlite::fromJSON(query, simplifyVector = FALSE, simplifyDataFrame = FALSE)
poly_geojsonsting <- jsonlite::toJSON(mydata$featurecollection[[2]]$feature, auto_unbox = TRUE)
poly <- geojsonio::geojson_sf(poly_geojsonsting)
poly
}
# Define location for delineation (Calapooia Watershed)
state <- 'OR'
latitude <- 44.62892
longitude <- -123.13113
# Delineate watershed
cal_ws <- streamstats_ws('OR', longitude, latitude) %>%
st_transform(crs = 5070)USGS StreamStats
nhdplusTools
-
nhdplusToolsis anRpackage that can access the Network Linked Data Index (NLDI) service, which provides navigation and extraction of NHDPlus data: https://doi-usgs.github.io/nhdplusTools/ -
nhdplusToolsincludes network navigation options as well as watershed delineation - The delineation method differs from StreamStats (based on National Hydrography IDs)
nhdplusTools
library(nhdplusTools)
# Simple feature option to generate point without any other attributes
cal_pt <- st_sfc(st_point(c(longitude, latitude)), crs = 4269)
# Identify the network location (NHDPlus common ID or COMID)
start_comid <- nhdplusTools::discover_nhdplus_id(cal_pt)
# Combine info into list (required by NLDI basin function)
ws_source <- list(featureSource = "comid", featureID = start_comid)
cal_ws2 <- nhdplusTools::get_nldi_basin(nldi_feature = ws_source)nhdplusTools
nhdplusTools
nhdplusTools works by walking a network of pre-staged sub-catchments with unique IDs (COMIDs)
Other watershed delination methods
- Outside of the U.S., these tools are not available
- It is still possible to delineate a custom watershed from raw DEM data with help from the
whiteboxR package - This book walks through this process
- Jeff Hollister (U.S. EPA) developed an R package called
elevatrthat can access DEM data from the web both within and outside the U.S.
Your Turn
- Delineate the Logan River watershed in Utah at -111.855, 41.707
- Use
mapview::mapviewto plot watershed
08:00
Solution
- Delineate Logan River watershed
# Logan River Watershed
latitude <- 41.707
longitude <- -111.855
# Define the lat/lon
start_point <- st_sfc(st_point(c(longitude, latitude)), crs = 4269)
# Find COMID of this point
start_comid <- nhdplusTools::discover_nhdplus_id(start_point)
# Create a list object that defines the feature source and starting COMID
ws_source <- list(featureSource = "comid", featureID = start_comid)
# Delineate basin
logan_ws <- nhdplusTools::get_nldi_basin(nldi_feature = ws_source)Solution
- Map the Logan River watershed
StreamCatTools
Why StreamCat/LakeCat?
- Examples covered are for single watersheds - but we often need data for hundreds or thousands
- Overlaying watersheds onto numerous landscape rasters/layers is complicated/long process
- StreamCat/LakeCat solves this issue by providing summarized data for all streams and lakes in the NHDPlus (medium resolution)
Why StreamCat/LakeCat?
Let’s revisit the Calapooia watershed and calculate percent row crop for 2019 with FedData
- Download NLCD for 2019
Why StreamCat/LakeCat?
- Use terra to extract the watershed metrics
Why StreamCat/LakeCat?
Now let’s extract the same information using the StreamCatTools package to access the online StreamCat database
StreamCatTools
- StreamCat and the
StreamCatToolspackage provide access to the same information with much less code because StreamCat pre-stages watershed metrics for each NHDPlus catchment
StreamCatTools
StreamCat also provides metrics at several scales
StreamCatTools
StreamCatTools
For a subset of watershed metrics, summaries within ~100m of the stream segment are also available for catchments and watersheds:
StreamCatTools
sc_get_data(comid = comid,
metric = 'PctCrop2019',
aoi = 'catchment,riparian_catchment,watershed,riparian_watershed') %>%
as.data.frame() COMID WSAREASQKM WSAREASQKMRP100 CATAREASQKM CATAREASQKMRP100
1 23763521 964.6101 136.17 8.4933 1.1097
PCTCROP2019CATRP100 PCTCROP2019WSRP100 PCTCROP2019CAT PCTCROP2019WS
1 9.08 8.4 36.59 10.49StreamCatTools
StreamCatTools also makes it very easy to grab data for entire regions.
StreamCatTools
StreamCatTools
StreamCatTools
- We can provide multiple metrics to the request by separating them with a comma.
- Note that the request is provided as a single string,
'PctCrop2001, PctCrop2019', rather than a vector of metrics:c('PctCrop2001', 'PctCrop2019'). - The request itself is agnostic to formatting of the text. For example, these requests will also work:
'pctcrop2001, pctcrop2019'or'PCTCROP2001,PCTCROP2019'.
StreamCatTools
StreamCat contains hundreds of metrics and we recommend consulting the metric list to identify those of interest for your study.
Accessing LakeCat
The R function to access LakeCat data was designed to parallel StreamCat functions
Let’s walk through an example together that:
- Define a
sfobject of a sample point at Pelican Lake, WI - Obtain the lake waterbody polygon
- Extract the COMID (unique ID) to query LakeCat
- Pull data on mean watershed elevation, calcium oxide content of the geology, % sand and organic matter content of soils, and % of the watershed composed of deciduous forest
Accessing LakeCat
library(nhdplusTools)
# Pelican Lake, WI
latitude <- 45.502840
longitude <- -89.198694
pelican_pt <- data.frame(site_name = 'Pelican Lake',
latitude = latitude,
longitude = longitude) %>%
st_as_sf(coords = c('longitude', 'latitude'), crs = 4326)
pelican_lake <- nhdplusTools::get_waterbodies(pelican_pt)
comid <- pelican_lake %>%
pull(comid)
lc_get_data(metric = 'elev, cao, sand, om, pctdecid2019',
aoi = 'watershed',
comid = comid)# A tibble: 1 × 7
COMID WSAREASQKM SANDWS ELEVWS CAOWS PCTDECID2019WS OMWS
<dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 167120863 41.0 59.6 491. 4.81 14.7 16.7Your Turn
Query LakeCat to determine if the basins of these lakes had more deciduous or conifer forest in 2019:
“9028333,9025609,9025611,9025635”
The LakeCat metrics page may help
05:00
Solution
library(StreamCatTools)
comids <- "9028333,9025609,9025611,9025635"
lc_get_data(metric = 'pctdecid2019, pctconif2019',
aoi = 'watershed',
comid = comids) # A tibble: 4 × 4
COMID WSAREASQKM PCTDECID2019WS PCTCONIF2019WS
<dbl> <dbl> <dbl> <dbl>
1 9025609 5.27 18.1 0
2 9025611 0.447 19.3 0
3 9025635 13.6 22.3 0.339
4 9028333 6.62 34.5 2.32 Bringing it all together
- To finish the workshop, we will walk through 2 examples of using
spmodelto model phenomena in two types of freshwaters:- Electrical conductivity of lake water across Minnesota
- The distribution of Argia damselfly across several northeastern states
Lake Conductivity
- Conductivity is an important water quality measure and one of growing concern due to salinization of freshwater (Cañedo-Argüelles et al. 2016, Kaushal et al. 2021)
- This analysis is based on a recent paper by Michael Dumelle and others published in the journal Spatial Statistics. The GitHub repository for this paper is also available
Data Prep: Conductivity (Dependent) Data
Load required packages…
Data Prep: Conductivity (Dependent) Data
Read and prep table of lake conductivity values…
# Read in states to give some context
states <- tigris::states(cb = TRUE, progress_bar = FALSE) %>%
filter(!STUSPS %in% c('HI', 'PR', 'AK', 'MP', 'GU', 'AS', 'VI')) %>%
st_transform(crs = 5070)
# Read in lakes, select/massage columns, convert to spatial object
lake_cond <- fread('nla_obs.csv') %>%
select(UNIQUE_ID, COMID, COND_RESULT,
AREA_HA, DSGN_CYCLE,
XCOORD, YCOORD) %>%
mutate(DSGN_CYCLE = factor(DSGN_CYCLE)) %>%
st_as_sf(coords = c('XCOORD', 'YCOORD'),
crs = "+proj=aea +lat_0=37.5 +lon_0=-96 +lat_1=29.5 +lat_2=45.5 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +type=crs") %>%
st_transform(crs = 5070)Data Prep: Conductivity (Dependent) Data
Data Prep: Conductivity (Dependent) Data
Data Prep: Conductivity (Dependent) Data
Select sample sites within Minnesota
Data Prep: Conductivity (Dependent) Data
Data Prep: Conductivity (Dependent) Data
Data Prep: LakeCat (Independent) Data
We will use the similar watershed predictors as Dumelle et al. (2023).
Already included with data table with the response variable are:
- Lake Area (AREA_HA)
- Sample year (DSGN_CYCLE)
Data Prep: LakeCat (Independent) Data
From LakeCat, we also will get the following predictor variables:
- Local long-term air temperature
- Long-term watershed precipitation
- Sulfur content of underlying lithology
Data Prep: LakeCat (Independent) Data
comids <- cond_mn$COMID
mn_lakecat <- lc_get_data(comid = comids,
metric = 'Tmean8110, Precip8110, S') %>%
select(COMID, TMEAN8110CAT, PRECIP8110WS, SWS)
mn_lakecat# A tibble: 115 × 4
COMID TMEAN8110CAT PRECIP8110WS SWS
<dbl> <dbl> <dbl> <dbl>
1 1099282 7.69 825. 0.0365
2 1101812 7.91 812. 0.0329
3 1768378 3.51 696. 0.0985
4 1775870 4.28 749. 0.272
5 1776124 4.43 778. 0.272
6 2032039 7.23 794. 0.0712
7 2034063 7.25 845. 0.0712
8 2262633 5.58 768. 0.0712
9 2262729 5.62 786. 0.0329
10 2350690 6.71 735. 0.0712
# ℹ 105 more rowsData Prep: LakeCat (Independent) Data
In addition to these static LakeCat data, we would also like to pull in data from specific years of NLCD to match sample years for % of watershed composed of crop area
To do this we will need to:
- Grab LakeCat NLCD % crop data for years 2006, 2011, 2016
- Clean and pivot the columns and add a year column
- Add 1 to each year since available NLCD are 1 year behind field samples
Data Prep: LakeCat (Independent) Data
crop <-
# Grab LakeCat crop data
lc_get_data(comid = comids,
aoi = 'watershed',
metric = 'pctcrop2006, pctcrop2011, pctcrop2016') %>%
# Remove watershed area from data
select(-WSAREASQKM) %>%
# Pivot table to long to create "year" column
pivot_longer(!COMID, names_to = 'tmpcol', values_to = 'PCTCROPWS') %>%
# Remove PCTCROP and WS to make "year" column
mutate(year = as.integer(
str_replace_all(tmpcol, 'PCTCROP|WS', ''))) %>%
# Add 1 to each year to match NLA years
mutate(year = factor(year + 1)) %>%
# Remove the tmp column
select(-tmpcol)Data Prep: LakeCat (Independent) Data
Now, join the tables to make our model data
Modeling lake conductivity
Define the formula
Modeling lake conductivity
Run a non-spatial and spatial model for comparison
cond_mod <- splm(formula = formula,
data = model_data,
spcov_type = 'none')
cond_spmod <- splm(formula = formula,
data = model_data,
spcov_type = 'exponential')
summary(cond_spmod)
Call:
splm(formula = formula, data = model_data, spcov_type = "exponential")
Residuals:
Min 1Q Median 3Q Max
-1.87192 -0.19602 0.02576 0.29597 1.28615
Coefficients (fixed):
Estimate Std. Error z value Pr(>|z|)
(Intercept) 8.486e+00 8.813e-01 9.630 < 2e-16 ***
AREA_HA 2.394e-05 5.510e-05 0.435 0.6639
year2012 -1.270e-01 3.261e-02 -3.896 9.80e-05 ***
year2017 -9.871e-02 3.851e-02 -2.563 0.0104 *
TMEAN8110CAT 5.375e-01 6.740e-02 7.976 1.55e-15 ***
PRECIP8110WS -8.406e-03 1.313e-03 -6.404 1.51e-10 ***
PCTCROPWS 4.317e-03 2.767e-03 1.560 0.1188
SWS 1.110e+00 7.740e-01 1.435 0.1514
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Pseudo R-squared: 0.5024
Coefficients (exponential spatial covariance):
de ie range
2.685e-01 1.371e-02 2.167e+04 Modeling lake conductivity
Model comparison
Modeling lake conductivity
Leave-one-out comparison
prd_mod <- spmodel::loocv(cond_mod, se.fit = TRUE, cv_predict = TRUE)
prd_spmod <- spmodel::loocv(cond_spmod, se.fit = TRUE, cv_predict = TRUE)
rbind(prd_mod %>% pluck('stats'),
prd_spmod %>% pluck('stats'))# A tibble: 2 × 4
bias MSPE RMSPE cor2
<dbl> <dbl> <dbl> <dbl>
1 -0.00261 0.270 0.519 0.731
2 -0.00392 0.140 0.374 0.860Map predicted values and standard errors
Join back to model data for mapping
Map predicted values and standard errors
Map predicted values and standard errors
Map predicted values and standard errors
Map predicted values and standard errors
Argia distribution
In this example, we will model the occurrence of the Argia damselfly in several northeastern states
finsyncR
To start this exercise, we’ll introduce a new R package called finsyncR. This package was developed by US EPA scientists and academic collaborators.
finsyncR
-
finsyncRprovides us with access to thousands of biological samples across the U.S. from both EPA and USGS sources (e.g., Rumschlag et al. 2023). We’ll be using EPA data today - The EPA data are from the National Aquatic Resources Assessment’s Wadeable Streams Assessment (2001-2004) and National Rivers and Streams Assessments (NRSA; 2008/2009, 2013/2014, and 2018/2019).
Data Prep: Biological (Dependent) Data
Load additional packages
Data Prep: Biological (Dependent) Data
Next, use finsyncR to get genus-level macroinvert data from just EPA and rarefy to 300 count
The code also converts the data to occurrence data (1 = detect, 0 = non-detect) and set a seed to make it reproducible.
macros <- getInvertData(dataType = "occur",
taxonLevel = "Genus",
agency = "EPA",
lifestage = FALSE,
rarefy = TRUE,
rarefyCount = 300,
sharedTaxa = FALSE,
seed = 1,
boatableStreams = T)
finsyncR is running: Gathering, joining, and cleaning EPA raw data
finsyncR is running: Rarefying EPA data
finsyncR is running: Applying taxonomic fixes to EPA data
finsyncR is running: Finalizing data for output
finsyncR data synchronization complete [1] 6174 856Data Prep: Biological (Dependent) Data
Clean data:
- Select columns of interest
- Remove EPA’s Wadeable Streams Assessment (2001-2004)
- Convert “CollectionDate” to a date (
lubridate::date()) and convert presence/absence to a factor - Convert table to a
sfobject and transform to EPSG:5070
Data Prep: Biological (Dependent) Data
# Flexible code so we could model another taxon
genus <- 'Argia'
taxon = macros %>%
dplyr::select(SampleID,
ProjectLabel,
CollectionDate,
Latitude_dd,
Longitude_dd,
all_of(genus)) %>%
#filter(ProjectLabel != 'WSA') %>%
mutate(CollectionDate = date(CollectionDate),
presence =
as.factor(pull(., genus))) %>%
st_as_sf(coords = c('Longitude_dd', 'Latitude_dd'), crs = 4269) %>%
st_transform(crs = 5070)Data Prep: Biological (Dependent) Data
Data Prep: Biological (Dependent) Data
Data Prep: Biological (Dependent) Data
Data Prep: Biological (Dependent) Data
Data Prep: Biological (Dependent) Data
For today’s exercise, we’ll narrow down the samples to the northeaster region of the U.S.
- Select states from the northeaster U.S.
- Select NRSA sample sites that intersect with these states.
- Filter to just the 2013/2014 and 2018/2019 sample periods.
- Create a new column for sample year.
- Select desired columns.
Data Prep: Biological (Dependent) Data
region <- states %>%
filter(STUSPS %in% c('VT', 'NH', 'ME', 'NY', 'RI',
'MA', 'CT', 'NJ', 'PA', 'DE'))
# Use region as spatial filter (sf::st_filter()) for taxon of interest
taxon_rg <- taxon %>%
st_filter(region) %>%
filter(ProjectLabel %in% c('NRSA1314', 'NRSA1819')) %>%
mutate(year = year(ymd(CollectionDate))) %>%
select(SampleID:CollectionDate, presence:year)
taxon_rg %>%
pull(presence) %>%
table().
0 1
485 65 Data Prep: Biological (Dependent) Data
Data Prep: Biological (Dependent) Data
Data Prep: Predictor (Independent) Data
- Obtain list of NHDPlus COMIDs that match sample sites from
nhdplusTools
- Use NLDI service via StreamCat to get the COMIDs
- Create a vector of COMIDs by splitting the COMID string
- Add COMID to our Argia occurrence table
Data Prep: Predictor (Independent) Data
Data Prep: Predictor (Independent) Data
- Get non-varying StreamCat data.
Data Prep: Predictor (Independent) Data
- PRISM air temperatures for sample periods
- The
prismpackage requires that we set a temporary folder in our work space. Here, we set it to “prism_data” inside of our “data” folder. It will create this folder if it does not already exist. - We then stack the climate rasters and use
terra::extract()to
Data Prep: Predictor (Independent) Data
Don’t worry - we’ll walk through this together
library(prism)
# Get these years of PRISM
years <- c(2013, 2014, 2018, 2019)
# Set the PRISM directory (creates directory in not present)
prism_set_dl_dir("./data/prism_data", create = TRUE)
# Download monthly PRISM rasters (tmean)
get_prism_monthlys('tmean',
years = years,
mon = 7:8,
keepZip = FALSE)
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tmn <- pd_stack((prism_archive_subset("tmean","monthly",
years = years,
mon = 7:8)))
# Extract tmean at sample points and massage data
tmn <- terra::extract(tmn,
# Transform taxon_rg to CRS of PRISM on the fly
taxon_rg %>%
st_transform(crs = st_crs(tmn))) %>%
# Add COMIDs to extracted values
data.frame(COMID = comid_vect, .) %>%
# Remove front and back text from PRISM year/month in names
rename_with( ~ stringr::str_replace_all(., 'PRISM_tmean_stable_4kmM3_|_bil', '')) %>%
# Pivot to long table and calle column TMEANPRISMXXXXPT, XXXX indicates year
pivot_longer(!COMID, names_to = 'year_month',
values_to = 'TMEANPRISMXXXXPT') %>%
# Create new column of year
mutate(year = year(ym(year_month))) %>%
# Average July and August temperatures
summarise(TMEANPRISMXXXXPT = mean(TMEANPRISMXXXXPT, na.rm = TRUE),
.by = c(COMID, year))Data Prep: Predictor (Independent) Data
Combine Dependent and Independent Data
Modeling occurrence of genus Argia
Model formulation
Modeling occurrence of genus Argia
Run non-spatial and spatial models for comparison
bin_mod <- spglm(formula = formula,
data = model_data,
family = 'binomial',
spcov_type = 'none')
bin_spmod <- spglm(formula = formula,
data = model_data,
family = 'binomial',
spcov_type = 'exponential')
summary(bin_spmod)
Call:
spglm(formula = formula, family = "binomial", data = model_data,
spcov_type = "exponential")
Deviance Residuals:
Min 1Q Median 3Q Max
-1.4200 -0.4453 -0.3030 -0.1717 2.6018
Coefficients (fixed):
Estimate Std. Error z value Pr(>|z|)
(Intercept) 9.603140 5.862970 1.638 0.10144
I(log10(WSAREASQKM)) 0.760753 0.190182 4.000 6.33e-05 ***
ELEVWS -0.007621 0.002402 -3.172 0.00151 **
WETINDEXWS 0.001087 0.003466 0.314 0.75384
BFIWS -0.050563 0.039372 -1.284 0.19906
PRECIP8110WS -0.002916 0.002653 -1.099 0.27172
TMEANPRISMXXXXPT -0.300855 0.140418 -2.143 0.03215 *
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Pseudo R-squared: 0.09293
Coefficients (exponential spatial covariance):
de ie range
2.458e+00 1.210e-02 3.703e+04
Coefficients (Dispersion for binomial family):
dispersion
1 Model comparison/performance
Model comparison/performance
# Function to convert from log odds to probability
to_prob <- function(x) exp(x)/(1+exp(x))
# loocv of non-spatial model
loocv_mod <- loocv(bin_mod, cv_predict = TRUE, se.fit = TRUE)
# loocv of spatial model
loocv_spmod <- loocv(bin_spmod, cv_predict = TRUE, se.fit = TRUE)
pROC::auc(model_data$presence, loocv_mod$cv_predict)Area under the curve: 0.7765Area under the curve: 0.9085Map predictions and standard errors
Extract values from loocv() object and join to model data for mapping
Map predictions and standard errors
Map predictions and standard errors
Map predictions and standard errors
Map predictions and standard errors
Acknowledgements
- Thank you so much for attending!
- Questions?
